This research is directed toward the isolation of specific nuclear proteins that serve as indicators of various autoimmune conditions and the physical and functional characterization of these antigens. Two such proteins are the Sm and RNP antigens. This proposal outlines plans to isolate these antigens in a homogeneous, immunologically-active form. Each antigen will be examined to determine its basic structure, with particular emphasis on protein and nucleic acid content, number of species and/or polymorphic forms, and the nature of any Sm and RNP interaction. The functional characterization will be predicated on an evaluation of each protein's nucleic acid-binding specificity, the corresponding functional domains and precise cellular localization. In a parallel vein, studies will be directed toward the production of monospecific antibodies primarily through the use of mouse hybridomas. Overall, the availability of purified antigens and corresponding antibodies should permit the development of standardized diagnostic tests and help to delineate the role of these proteins in the sequence of events that is the autoimmune resonse. These studies are to be expanded toward the characterization of other nuclear proteins, with particular emphasis on the use of new methodologies such as nitrocellulose protein blots and the cloning of mouse hybridomas to identify new autoimmune-associated antigens.